It's been a surprisingly sleepy year for Initial Public Offerings -- or IPOs. Just 169 companies went public in 2015, 40% fewer than the debutantes hitting the market a year earlier according to Renaissance Capital. There was also a lot less money raised by these new investments, with the dollar value of IPOs shrinking to $30 billion in 2015 after clocking in at $85 billion in 2014.

Many IPOs got postponed as market sentiment cooled. Some of the most hyped private companies, including Uber, were able to raise money without listing on the stock exchange. There were still plenty of winners and losers among the companies that did go through with the IPO process. Let's take a look at some of the market freshmen of 2015.

The best IPOs 
Spark Therapeutics (ONCE) has soared 122% since going public in January as of the stock's Dec. 10 close. The developer of gene therapy treatments for orphan retinal dystrophies was initially expecting to price its offering between $19 and $21, but hot demand pushed that up to $23. It popped at the open and hasn't looked back. In October, the shares got a big boost after Spark announced positive results from a late-stage clinical trial for its lead therapy product candidate.

Seres Therapeutics (MCRB 2.94%) is another biotech that has more than doubled in 2015. The company behind a leading microbiome therapeutics platform went public this summer at $18, and the stock is now trading 106% higher. It's still losing money, but that's common for upstart biotechnology companies. It recently announced that it has enough cash to fund its operations through at least the first half of 2017.

Shake Shack (SHAK -0.56%) rounds out the list of the three best-performing debutantes of the 2015 class. The New York-based counter-service restaurant known for its gourmet burgers and fancy frozen custard treats has expanded quickly, and robust comparable-eatery sales validate the concept's growing popularity. Shake Shack hit the market in January priced at $21, and it has gone on to more than double. The shares have given back a lot of its earlier gains since peaking at $96.75 in May, but those who have held on are still looking at a juicy 105% return.

The worst IPOs 
MaxPoint Interactive (NYSE: MXPT) has surrendered 88% of its value since hitting the market at $11.50 in March. The marketing company behind the Digital Zip technology that helps generate in-store sales has seen sales grow -- up 33% in its latest quarter -- but the market's concerned about growing losses. MaxPoint is growing its customer base, but it will need to do so profitably if it wants to win back the market.

Zosano Pharma (ZSAN) has also had a rough rookie season. Zosano has a proprietary transdermal microneedle patch system for the delivery of drug formulations through the skin. Zosano took a hit in September after discontinuing the development of a daily treatment for severe osteoporosis and breaking off a collaboration with Eli Lilly. The IPO that seemed so promising at $11 has gone on to shed 77% of its value.

Belloran Pharmaceuticals (BLPH -4.39%) was another volatile biotechnology company. It's not a surprise to see upstart biotechs dominate the list of top and worst performers. Belloran may have once excited investors with the prospects for its pulmonary arterial hypertension treatment, but it went on to shed three quarters of its value in 2015.

There will always be winners and losers within the IPO class, and investors hope they get a broader selection of rookies in 2016.